Internal-combustion engine



Sept. 26, 1944. e. c. EVANS 2,358,797

INTERNAL- COMBUSTION ENGINE Filed Jan. 27, 1943 KNVBNTO Patented Sept. 26, 1944 2,358,797 INTERNAL-COMBUSTION ENGINE George G. Evans. United States Navy application January 27 j 9 Claims. (Granted ,.-1943, Serial No. 473,697

nnder the act oi M0113, 1883, as

amended April 3t, 1928; 370 0. G. 757) This invention relates to an improvement in internal combustion engines whereby an engine of sufilcient power for maximum requirements is provided with means whereby it may be operated under continued part loads with better fuel economy than is possible with present engines.

Many power plants in use at present are de signed to carry high loads, which are applied only during a small portion of their total time of operation In internal combustion engines, suchas used in automobiles today, full power is seldom used in normal city driving, and most of the operation is done at comparatively low loadsat which the fuel economy is usually very poor. Smaller engines with better economy for these loads are normally not desirable because of their poor acceleration characteristics and because at times when it is desired to apply higher loads, the necessary power is not available.

The object of the present invention is to provide an engin which may be operated to give comparatively good fuel economy at low loads, when desired, as well as at full load.

A further object is to form the combustion chamber of an internal combustion engine in two or more parts which may be connected for operation as one large chamber for high powers, or any number of which less than the total may be used when operating at correspondingly lower loads while the remaining parts are merely draw-' ing in and discharging atmospheric air.

Further and more specific objects will become apparent as the description of this engine proceeds.

In the accompanying drawing, the single fig- A fuel mixture, or air in case of injection type engines, is admitted from the manifold 5 through the inlet valve a into the combustion space which consists of only chamber 3 if the control .valve t is in the position shown, while chamber l acts- The passage 5 is connected to the exhaust manifold through exhaust valve l0. Both chamum shows a cross-section through the axis of one of the cylinder units normal to the crankshaft of an engine which may have any number of such cylinders arranged in any of the known cylinder arrangements.

The form of engine cylinder shown illustrates a preferred arrangement of parts, althoughit is obvious that various modifications in shape, di-

mensions and arrangement may be made without departing from the scope of the present invention.

In theillustrstion shown a steppe piston I reciprocal-tea in a correspondingly stepped cylinhers 3 and i may be supplied with ignition means ii. The piston pin 52 is connectedto the crank shaft M by means of connecting rod it. Any

lubricating system may be used, having a normal oil level in the crankcase as shown at it.

The operation of thisengine is similar'to that of any other internal combustion engine. If it is to be used as a carburetor type four-stroke cycle engine, the fuel mixture is admitted to one or both chambers simultaneously, depending on the position of control valve 8, during suction on the downstroke of the piston; it is then compressed on the upstroke and ignited for delivering the power on the following downstroke, after which the exhaust valve, is opened for exhausting during the following upstroke. This completes one of the consecutive cycles followed by the engine during operation.

The novel chamber connection is also app1ica-' ble to two-stroke cycle engines and to fuel-injection type internal combustion engines, and even to steam engines of the reciprocating type.

when extended low power operation is anticipated, valve 8 is turned in the position shown in the figure. Under these conditions the chamber 8 may bedesigned to operate in its range of powers near that which gives best fuel economy,

acceleration and high loads. Thus high power is rendered immediately available, yet fuel economy does not have to be sacrificed while normally operating under low. loads, as is now the case with most, of the high powered automobile en- 2 assays? gines used for long intervals to drive an automobile at comparatively low speeds on level streets.

During operation at lower loads with only chamber 3 operating as a combustion space, only a negligible amount oi power is used up in drawing in and exhausting atmospheric air because the ports are comparatively large. This air pumping is furthermore useful as an additional cooling means for helping to maintain the piston at the best operating temperatures when the throttle is wide open at high engine speeds.

In operation of the subject engine, whether it is composed of one cylinder unit or more. there would be as many power stages available as the engine contained combustion chambers per unit.

The operation of the cut-out or control valve it may be automatically controlled to react to a balance between engine load and throttle position, or engine load and speed.

The purpose of the improvement here disclosed may be defined in general as being: to permit the power output of an engine to be increased or diminished through several ranges or stages, without materially changing the engine speed beyond'a normal range for which it is designed to give best fuel economy; to accomplish an economy in fuel combustion for engines whose performance includes uneven load periods; to produce a multi-power-stage engine in which, at no time, are any of-the moving parts out of balance, nor thetiming of valves or ignition altered; and to permit of a variety of power stages in a combustion engine without greatly increasing its overall size or weight beyond average requirements.

Those parts of the subject engine not shown in the illustration are common to standard combustion engine design. Force feed oiling is utilized to lubricate those step-piston surfaces farthest from the crankcase.

It is understood that this invention is to be limited only by the scope of the appended claims and not by the specific form of the illustrative example herein shown and described.

This invention may be made and used by or for the Government of the United States for governmental purposes without the payment to me of any royalties thereon or therefor.

What is claimed is:

1. In a reciprocating engine, having one or more cylinders, the combination of several combustion or. working chambers, formed within each of the said cylinders, and means for connecting said combustion or working chambers for operation separately or in combination in accordance with the relative load applied.

- 2. In a reciprocating engine, having one or more cylinders, the combination of several combustion or working chambers, formed within each of the said cylinders, and valve means for connecting said combustion or working chambers, for operation separately or-ln combi-.

.nation to apply their respective pressures upon a common connecting rod.

3. In a. reciprocating engine, having one or more cylinders, the combination of a step-piston within a step-cylinder; the spaces between the walls of the said step-cylinder and the heads 4.111 a reciprocating engine, having one or more cylinders, the combination of a step-piston within a step-cylinder; the spaces between the walls of the said step-cylinder and the corre= spending heads of the said step-piston comprising several combustion or working chambers; means for interconnecting said combustion or working chambers to have communication, separately or in combination, with the intake and exhaust valves or ports, or with the atmosphere as may be selected;

5. In a reciprocating engine, having one or more cylinders, the combination of several combustion or working chambers formed within each of the said cylinders, means for interconnecting said combustion or working chambers so that some have communication, in combination, with one or more intake-valves or ports, and one or more exhaust-valve or ports while the balance are in communication with the atmosphere.

6. In a reciprocatingengine, having one or more cylinders, the combination of several combustion or working chambers formed within each of the said cylinders, means for interconnecting said combustion or working chambers to be operative separately or in combination, those chambers not in operation to have free and continuous access to atmospheric air.

7. In an engine, a stepped piston operating in a correspondingly stepped cylinder to form a corresponding number of displacement chambers, admission and exhaust valves connected directly to one of said chambers, and two-way cut-out valves in passages between said chamber and each of the other chambers for selectively interconnecting said chambers respectively, or cutting them 011 while connecting the corresponding other chamber to the atmosphere.

8. In an engine, a stepped piston operating in a correspondingly stepped cylinder to form a corresponding number of displacement chambers,

admission and exhaust valves connected directly to one of said. chambers, two-way cut-out valves in passages between said chamber and each of the other chambers for selectively interconnecting said chambers respectively, or cutting them of! while connecting the corresponding other chamber to the atmosphere, and means responsive to the load applied to the engine for cutting out one or more of said other chambers by means of the corresponding cut-out valves in accordance with the magnitude of the load requir men s maintain approximately full power operating conditions in the operating chambers.

9. In' an engine, a stepped piston operating in a correspondingly stepped cylinder to form a corresponding number of displacement chambers, admission and exhaust valves connected directly to one of said chambers, two-way cut-out valves in passages between said chamber and each of the other chambers for selectively interconnecting said chambers respectively, or cutting them ofi while connecting the corresponding other chamber to the atmosphere, and means responsive to the engine speed for cutting out one or more of said other chambers by means of the corresponding out-out valves in accordance with the speed of the engine to maintain the speed within a. range for which the engine is designed to run most economically with the corresponding chambers in operation.

' GEORGE c. EVANS. 

